Recoverable Heat Exchanger

ABSTRACT

A modular heat exchanger that can be submerged to great depths and then easily recovered in order to reduce the costs and disadvantages of the prior art. Because the heat exchanger is submergible and recoverable, it can be more easily maintained. This ease of maintenance allows the heat exchangers to be deployed at greater depths. This, in turn, allows for greater differences in temperatures, greater efficiency for the heat engine, and a more effective ocean thermal energy conversion system.

FIELD OF THE INVENTION

The present invention relates to heat exchangers in general, and, more particularly, to ocean thermal energy conversion.

BACKGROUND OF THE INVENTION

Ocean thermal energy conversion systems are systems that generate electricity by harnessing the difference in the temperature of the ocean at the surface and the temperature of the ocean at depth.

Sunlight cannot penetrate deep in the ocean, and, therefore, the temperature deep in the ocean is constantly cold. In contrast, the water at the surface is heated by the sun and is warmer. A heat engine uses this temperature difference to create kinetic energy, which can be used, for example, to generate electricity.

As the temperature difference between the cold water and the warm water increases, the efficiency of the heat engine increases. One way to effectively harness the temperature difference between the cold water and the warm water is to place the heat engine and the heat exchangers as far from one another as possible. This means placing the cold water heat exchanger as deep in the water as possible.

The problem with placing the cold water heat exchanger deep in the ocean is maintaining the heat exchanger. In order to operate these systems effectively, the heat exchangers must be cleaned and maintained regularly. Sea water is highly corrosive to the metal used in heat exchangers, causing oxidation and leaks. Another problem is that ocean life, like barnacles and seaweed, grow on the heat exchangers. This is difficult and costly to do when the heat exchangers are deep in the ocean.

FIG. 1 depicts a schematic diagram of the salient components of an ocean thermal energy conversion system in the prior art. FIG. 1 comprises heat engine 101, pipe 102-1, pipe 102-2, heat exchanger 103, and water surface 104.

SUMMARY OF THE INVENTION

The present invention is a modular heat exchanger that can be submerged to great depths and then easily recovered in order to reduce the costs and disadvantages of the prior art.

Because the heat exchanger is submergible and recoverable, it can be more easily maintained. This ease of maintenance allows the heat exchangers to be deployed at greater depths. This, in turn, allows for harnessing greater differences in temperatures, greater efficiency for the heat engine, and a more effective ocean thermal energy conversion system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a schematic diagram of the salient components of an ocean thermal energy conversion system in the prior art.

FIG. 2 depicts a diagram of the salient components of ocean thermal energy conversion system 200 in accordance with the illustrative embodiment of the present invention as it is configured at time t₀.

FIG. 3 depicts a depicts a diagram of the salient components of ocean thermal energy conversion system 200 in accordance with the illustrative embodiment of the present invention as it is configured at time t₁.

FIG. 4 depicts a diagram of the salient components of the illustrative embodiment of the present invention as it is configured at time t₂.

DETAILED DESCRIPTION

FIG. 2 depicts a diagram of the salient components of ocean thermal energy conversion system 200 in accordance with the illustrative embodiment of the present invention as it is configured at time t₀. Ocean thermal energy-conversion system 200 comprises: heat engine 201, flexible conduit 202-1, flexible conduit 202-2, heat exchanger 203, and water surface 204.

Although the illustrative embodiment comprises two conduits connecting heat engine 201 to heat exchanger 203, it will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention that comprise one or more conduits.

Although the illustrative embodiment comprises one heat exchanger, it will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention that comprise two or more heat exchangers.

Although the illustrative embodiment comprises one heat engine, it will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention that comprise two or more heat engines.

Although heat engine 201 floats, partially submerged, on water surface 204, it will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention in which heat engine 201 is completely out of the water (e.g., upon a platform, is on land, etc.) or is submerged.

Heat engine 201 is a device that converts thermal energy into mechanical energy. This mechanical energy can in turn be converted into electricity if so desired. In the illustrative embodiment, the heat engine runs on the Rankine cycle. In the illustrative embodiment of the present invention, heat engine 201 is floating on ocean surface 204. The heat engine can take advantage of the difference in the temperature of water surface 204 and the temperature difference between ocean surface 204 and the temperature of submerged heat exchanger 203. In any event, it will be clear to those skilled in the art, after reading this disclosure, how to make and use heat engine 201.

Conduit 202-1 and conduit 202-2 are flexible conduits which connect heat exchanger 203 and heat engine 201. The working fluid is transported between heat exchanger 203 and heat engine 201 through conduit 202-1 and conduit 202-2.

Although the illustrative embodiment comprises flexible conduits, it will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the present invention in which some or all of the conduits are not flexible.

In accordance with the illustrative embodiment, the working fluid would be ammonia, but it will be clear to those skilled in the art, after reading this disclosure that other fluids can be used, such as water (sea water or fresh water). In any event, it will be clear to one skilled in the art, after reading this disclosure how to make and use conduit 202-1 and conduit 202-2.

Heat exchanger 203 is a device for heat transfer. In the illustrative embodiment, heat exchanger 203 takes in warm fluid from heat engine 201 and cools the warm fluid, condensing it and then it flows back to heat engine 201.

Although the illustrative embodiment has heat exchanger 203 comprising a condensing cycle, it will be clear to those skilled in the art, after reading this disclosure, how to make and use alternative embodiments of the heat exchanger 203 in which it performs the vaporization part of the cycle. In any event, it will be clear to one skilled in the art, after reading this disclosure how to make and use heat exchanger 203.

FIG. 3 depicts a depicts a diagram of the salient components of ocean thermal energy conversion system 200 in accordance with the illustrative embodiment of the present invention as it is configured at time t₁. FIG. 3 comprises: heat engine 201, flexible conduit 202-1, flexible conduit 202-2, heat exchanger 203, and water surface 204.

FIG. 4 depicts a diagram of the salient components of the illustrative embodiment of the present invention as it is configured at time t₂. FIG. 3 comprises: heat engine 201, flexible conduit 202-1, flexible conduit 202-2, heat exchanger 203, and water surface 204.

Although the illustrative embodiment depicts heat exchanger 203 and heat engine 201 at the same altitude, it will be clear to those skilled in the art, after reading this disclosure how to make and use alternative embodiments of the present invention wherein the heat exchanger is at any depth and distance from the heat engine.

It is to be understood that the disclosure teaches just one example of the illustrative embodiment and that many variations of the invention can easily be devised by those skilled in the art after reading this disclosure and that the scope of the present invention is to be determined by the following claims. 

1. An apparatus comprising: a heat engine; and a heat exchanger for providing fluid to the heat engine; wherein the distance between the heat engine and the heat exchanger is d₁ at time t₀ and d₂ at time t₁, wherein d₁≠d₂ and t₀≠t₁.
 2. The apparatus of claim 1 further comprising: a first flexible conduit for carrying fluid from the heat exchanger to the heat engine at both time t₀ and time t₁.
 3. The apparatus of claim 2 further comprising: a second flexible conduit for carrying fluid from the heat engine to the heat exchanger at both time t₀ and time t₁.
 4. The apparatus of claim 1 wherein the ambient temperature surrounding the heat exchanger at time t₀ is different than the ambient temperature surrounding the heat exchanger at time t₁.
 5. The apparatus of claim 1 wherein the heat exchanger is positively buoyant in sea water.
 6. An apparatus comprising: a heat engine at a first altitude a₀ at time t₀ and time t₁, wherein t₀≠t₁; and a heat exchanger for providing fluid to the heat engine; wherein the heat exchanger is at the first altitude a₁ at time t₀ and at a second altitude a₂ at time t₁, wherein a₁≠a₂.
 7. The apparatus of claim 6 further comprising: a first flexible conduit for carrying fluid from the heat exchanger to the heat engine at both time t₀ and time t₁.
 8. The apparatus of claim 7 further comprising: a second flexible conduit for carrying fluid from the heat engine to the heat exchanger at both time t₀ and time t₁.
 9. The apparatus of claim 6 wherein the ambient temperature surrounding the heat exchanger at time t₀ is different than the ambient temperature surrounding the heat exchanger at time t₁.
 10. The apparatus of claim 6 wherein the heat exchanger is positively buoyant in sea water. 